At the beginning of the current century, P. Wilski, orienting a 1090 m deep mine in Příbram, found that measurements of the adjacent angles at air movement in the shaft and in the absence of this movement give a discrepancy of 11'31”. Based on this and on the data of visual observations of air movement in the shafts, he put forward a hypothesis about the helical movement of air along the shaft, affecting the magnitude of the weight deviation a. He determined the magnitude of the deflection a using the formula ...